Relay system for diesel electric locomotives



C. S. SNAVELY RELAY SYSTEM FOR DIESEL ELECTRIC LOCOMOTIVES Jan. 9,1951

Filed March 6, 1947 n m n n f 1 m M m .0 hp a 7m M Z p ea .mfi mf PD Baldy if? pz'ofied up --Y ljppep leuel APpz'olzedap Z0 15' CaPPenzlZlLr'zhg-+ f jlowqrlewlIE! Belay aw M S I m wa fvw l m Mi m w MM 2 w 5 F 0 Patented Jan. 9, 1951 STATES OFFICE:

nnmrsrsrsmiron nmseiiniino'mro LOCOMOTIVES I 'Glarenc'e: S. Snavely, Churchill: Borough, Pa -as signortol he Union-Switch:&1-S ignalGompany, swissvale la i acorporation of- Bennsylvania Application March 6, 194?; Serial N0.-732,771

invention relates to relay systems" and particularly to relay systems; adapted to 1 provide an accurate response t'o sensitive-relays of the meter typo; It has been found desirable: in some relay applications" to initiat'e" orchange: a control only upon the closure of relay" contacts but not upon the opening of contacts. This arrangement is advantageous=- in applications wheresensitive relays of 'the' meter type are usedQand i's occasioned by the fact that thecontactstructures of" relaysof" this type are in herently' fragileand limited to extremely light duties s'othat thecontacts m'ay be used to establisli a circuit through i which current 'isinitiated but areunable to" withst'and the arcing and burning which accompanies the interruption" of='-a current"at such' contactelements; I

It has also" been" found necessary in these applications to providea system arranged so as to check the integrity of' the circuit elements used te establish and maintain the" operated condition of the apparatus. system organizationl issuch that the apparatus assumes i or: maintains its operated position" only Sh lling as energy is supplied thereto; so that any raiiure of the circuit elements sup i ingenergy to the apparatus fbr: establishing and maintainin operated condition will! either "prevent operationi of the apparatus to its -operatecf: posi ticm. or: will result in railingto maintain the apparatus inits operated position.

It is 'an object on my inventionr'to provide a novel: andi improved? relay system incorporating airepeated relay coop crating with: a master r elay andi arranged sci as to? obtain operation of the repeater relay'only 'whemcontacts' of: the master relays'cibseibutY-notiwhen :such contacts'openz 7.

Another okijeetl is to: proVideZaaLnoveILand; im' moved: relay system? wherein: a1) master: relay controls-.1 a: repeater" relay between? normaif' and operated conditions by? circuits arranged to". effect operatiorr :of '4 the repe'aten' relay: only; when the master relay contacts'sclose andu 'iwhicl'ncircuit's the-- master relay contacts are neverfrequiredz-to interrupt ai flow-ai current;

A. further object: is to mrov ide: a system of: the type described 'abov'e;, in: which: the: relays and circuits are arranged so that: thee repeater relay assumes; andzmainta-ins': its operated: condition only-solong-sas :itiiS energizedt Y The above mentioned-rand other important ob.- jects and characteristic featuresci:my invention are obtained byrproviding anmasten'reiayfwithia two-winding repeater. relay: The: master: relay ltestablishenthroughzoneioriitsscontaetsia .piclisup circuit ifor therrepeater relay including the two windingsof the relay cumulatively energized,

; shunting: the" other of: its windings and'the contact of the master-"relay in the pick-up circuit, and" the" rna'sterrelay also establishes through another of its' contactsa releas'e' circuit including the other'windingiof the repeater relay energized in: omzio'sition to I the'stick winding", with the stick contact of the: repeater relay interrupting the release: circuit" carried through: the contact of the masterirelayi 1 I sh'all describe one form of apparatus embodyingmyinventi0n and.v shall thenpoint out the novel features thereof: in claims.

In-theiaccompanyingdrawings; Fig; 1 is .a diagrammat'ic' View illustrating a preferred form of apparatus embod yingmyinvention; Fig. 2 is a diagrammatic? representation" of the different cond'itions of operationof repeater relay KP obta'ining according as (a) current is rising in master r'elay MR; or (b) currentisfalling in master relayMR'.

Referring-"to Figpl-i the reference character MR designates a sensitive relay of the meter typeschematically shown as comprising a horseshoe shaped' permanent magnet l provided with confronting pole pieces2 betweenwhich a magnetizable" member 3"is pivotally mounted for rotation about an axis perpendicular to the plane of magnet I; The member 3 carries a pointer orfi'nger land i'sbiased in the customaryimanner', as by a* spring, to cause finger 4' to assumea first position which may, for

example, be" an ex-treme'left hand position as viewed in Fig. 1. Member 3 also is provided with a coil 'or winding 5 which when energized by current of suitable polarity creates a flux which cooperates wi ththe permanent magnetic flux existing between polep'i'eces 2: to rotate member 3 in a; clockwise-direction ('as viewed in Fig. l) to a= .position determined by the strength'of the biasing spring and the relative values of the permanentmagnetic-field and flux due to currentin: winding 5. Relay MR. also includes a first contact element 6 disposed to engage finger 4i when that finger'is positioned in its first or leit h'and position, and a second" contact element 1 dis-posed:to engage finger 4 when member 3 is rotated clockwis'eto the position where finger 4 occupies anOther 'eXtreme or right-hand position as vi'ewed" iii-Fig: 1i The arrangement is thus i sue/h tl'i'at "finger 4 engages contact element 6 hereinafter referred to as the lower level, at which member 3 operates finger 4 out of engagement with element 3, and finger 4 engages contact element 1 when the energization of coil 5 is at or above the level, hereinafter referred to as the upper level, at which member 3 is rotated to position finger 4 in engagement with element 1. When coil 5 is energized at a value intermediate the lower and upper levels just mentioned, finger 4 is then disposed intermediate contact elements 6 and I and is disengaged from each of those elements. It is to be understood or course that the various elements of relay MR are suitably housed and that external terminals may be provided on the housing for establishing circuit connections with the relay elements.

The contact elements 6 and I and finger 4 of relay MR are proportioned in accordance with the torque available for operation of member 3 and assuming that relay MR is designed to perate on a very low degree of energization of coil it will be assumed that finger 4 and contact elements 6 and I are of the light duty type capable of handling relatively low currents ranging in the milliamperes using a low voltage source capable of delivering only a few volts.

In order to detect the operation of relay MR, I provide a repeater relay of the biased polar type such as thatshown and claimed in Letters Patent of the United States No. 2,283,270, granted on May 19, 1942, to Robert M. Laurenson for Electrical Relay. Relay KP comprises two windings 8 and 9 and an armature suitably biased as explained in Patent No. 2,283,270, to one extreme position which I shall term a normal position, and operable to another extreme position, which I shall term a reverse position, only when the net resultant flux in the relay due to windings 8 and 9 is in the proper direction and is sufficient in magnitude to overcome the armature bias. The windings 8 and 9 are provided on the relay in such a manner that either winding creates flux of the proper direction to counteract the bias of the armature and operate that armature to its reverse position only when current flows through the winding in the direction indicated in the drawing by an arrow associated with that winding, or from left terminal to right as viewed in Fig. 1. Accordingly, energy flowing in either winding from its right terminal to its left not only is ineffective to create flux of the proper direction to counteract the armature bias, but on the other hand creates a flux tending to assist the bias of the armature. This type of relay responds quickly to relatively low energy levels in the relay and will operate properly on the limited amount of power that can, without causing injury to the elements, bepassed through the contacts of master relay MR.

Relay KP is controlled by relay MR through the medium of circuits supplying current to relay KP from a suitable source, such as a battery having its opposite terminals designated by the reference characters B and C with the current from the source being assumed to flow from terminal B through various circuit elements to terminal C. A pick-up circuit for relay KP may be traced from terminal B through contact 64 of relay MR and windings-8 and 9 of relay KP, in

series, to terminal C.-;It will be noted that the Y direction of current flow in the pick-up circuit is such that both windings 8 and 9 are traversed by energy from left terminal to right so that the two windings act cumulatively to generate a flux opposing and counteracting the bias of the arma- 4 ture of relay KP to cause that armature to operate to its reverse position. It will also be noted that with windings 8 and 9 connected in series in the pick-up circuit the resistances of the windings: are additive to limit the current flow in the circuit but due to the cumulative action of the fluxes the magnetomotive forces produced at the limited current value is sufiicient to cause relay KP.to operate its armature to its reverse position. This operation of relay KP drives contact finger I!) carried by the armature of relay KP, into engagement with contact element l2 and establishes a stick circuit which may be traced from terminal B through contact l2lll of may KP,- and winding 9 from its left terminal to its right terminal and then to terminal C. The stick circuit-places a short circuit across contact 64 of relay MR and winding 8 of relay KP, so that the resistance of that winding accordingly is cut out of circuit with winding 9 with the result that the value. of current caused to flow in winding 9 under these conditions is greater than the current flow which obtains when windings 8 and 9 are in series'and contact Ill-l2 of relay KP is open. The-resistances and number of turns of windings 8 and 3 are preferably so proportioned that with winding 8 shunted, winding 9 is energized at a level such as to produce substantially the same value of magnetomotive force that is produced when windings 8 and 9 are energized cumulatively in series. The stick circuit of relay KP accordingly is eilective when completed to hold its armature in its reverse position and will do so in the event that contact 64 of relay MB is opened. If this contact is opened it is to be noted thatthe contact merely interrupts a shunted cir-' cuit path so that there is no danger to the sensitive light duty contact elements due to arcing or burning which accompanies the interruption of a current through contact elements.

Assuming that relay KP is held energized over its stick circuit and that contact 64 of relay MR has opened without danger to its parts, relay KP will'remain energized until such time as relay MR closes its other contact 4-1. This contact establishes a release circuit which extends from terminal 13 through contact l2-l0 of relay KP, winding 8 of relay KP from its right terminal to left, and contact 4-1 of relay MR to terminal C. It will be noted that the flow of current in winding 8 due to the release circuit is in the direction to create flux aiding the armautre bias, and that winding 8 accordingly creates a flux opposite in direction to the flux created by winding 9 energized in its stick circuit. The windings 8 and! are now connected in parallel circuit paths. across the source and because of the previously mentioned proportioning of the parts each winding will be capable of creating a flux substantially cancelling the flux creat d by the other winding, so that the net resultant flux created by the two' windings would have a value of substantially .zero magnitude in relay KP if the energized conditions of the two windings were maintained. Before such a total cancellation of flux obtain-s, however, the resultant flux in relay KP will decrease to'a point below that required to maintain the armature in its reverse position in opposition to its bias, with the result that the armature will respond to its bias and operate to its normal position to open contact l2l0 and thereby deenergize both windings 8 and 9. The flux in relay KP due to windings 8 and 9 will therefore decay to a zero value.

With relay KP in its normal position,-contact thereby"sassuringzthat' a failure of any circuit .element will result either in failure of relay KP to' operate, or in restoration of the relay to its normal position. Q. It is also to be noted that the relay system "functions in such a manner that once relay KP is picked up it remains picked up until contact 4-1 of relay MR closes, and once relay KP is released it remains released until contact 6-4 of relay. MR closes. The condition of relay KP established upon closure of either contact of master relay MR is therefore maintained until the other contact of the relay subsequently closes, and the released or picked-up condition of relay KP :in the intermediate range of energization of relay MR is determined by the particular contact of the master relay that last caused a change in operation of relay KP. As indicated in Fig.2, the condition assumed by relay KP in the intermediate position of master relay MR (where finger 4 is disengaged from both contact elements 6 and 1) accordingly differs depending upon whether the last operation of relay KP was occasioned by a contact of relay MR closed because of current rising in th load circuit, or falling in such circuit. Diagram 2(a) of the drawing represents the operation of relay KP obtaining when current in the load circuit rises in value from below the lower level to above the upper level, the relative values of current being indicated along the horizontal line. This diagram indicates that in such case relay KP, which was in its picked-up position with current in the load circuit below its lower level, remained picked up until the upper level of load current was reached, whereupon relay KP was caused to release. Diagram 2(1)) represents the operation of relay KP when current in the load circuit falls from above the upper level to below the lower level. This diagram indicates that in the case of falling load current relay KP, which was released with current in the load circuit above its upper level, remains released in the intermediate range of load current and until the load current reaches its lower level, whereupon relay KP picks up.

An advantage of a relay system embodying my invention is the arrangement whereby a master relay controls a repeater relay by circuits arranged to effect operation of the repeater relay only when the contacts of the master relay close, and in which circuits the master relay contacts .are never required to interrupt a flow of current. The arrangement therefore permits a master relay of the sensitive meter type having inherently fragile contacting elements to establish different controls with the minimum of damage to the contacting elements of the relay.

Although I have herein shown and described but one form of relay system embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. A relay system comprising a two-windingrelay having contact means operated between opened and closed positions according as said relay is released or picked up respectively, contact elements movable to first and second'circuit closing positions, a source of current, a pickup circuit including said source and both'of the relay windings connected in series to create additive fluxes to pick up the relay and completed by saidcontact elements in their said first circuit closing po-- sition; whereby the picking up of "saidrelay checks the integrity of both windings of said relay and their respective circuit connections, a holding circuit including said source and one of said two windings and completed by said contact means inits closed position, said holding circuit establishing a short circuit across the portion of the said pickup circuit that includes the other of said two windings and said contact elements in their first circuit closing position, and a release circuit including said source and said other winding and said contact means in its closed position and completed by said contact elements in their second circuit closing position, said other winding when energized in its release circuit creating a flux opposing that set up by the said one winding energized in its holding circuit.

2. A relay system for controlling the propulsion system of a Diesel-electric locomotive having a prime mover connected through an electrical generator and a load circuit to the wheel driving motors of said locomotive, said relay system comprising a meter type master relay responding to energy from said load circuit and having contact elements including a first and two cooperating second elements relatively movable to first and second circuit closing positions in which said first contact element respectivelyengages one .or the other of said two second contact elements, a two-winding polar biased repeater relay having an armature biased to a first position and operable to a second position when the .net resultant flux in said relay is in a given direction and above a given level, contact means operated by said armature comprising a fixed member anda single cooperating movable member operated to opened or closed positions with respect to the fixed member accordingas said armature occupies its said first or second position respectively, a source of current, a pickup circuit including said source and both windings of said repeater relay connected in series to create additive fluxes having a net resultant in said given direction and above said given level to operate said armature to its said second position and completed by the contact elements of said master relay in their said first circuit closing position, whereby the operation of said armature of .said repeater relay to its said second position checks the integrity of both windings of said repeater relay and their respective circuit connections, a holding circuit including said source and one of said two windings of said repeater relay and completed by the movable member of said contact means in its closed position, said holding circuit shunting the other of said two windings of said repeater relay and the contact elements of said master relay in their said first circuit closingposition, and a release circuit including said source and the movable member of said contact means in its closed position and said other winding of said repeater relay and completed by the contact elements of said master relay in their said second circuit closing position, said other winding when energized in its release circuit creating a fiux opposing that set up by the said one winding energized in its holding circuit.

3. In combination with a meter type master relay having contact elements including a first and two cooperating second elements relatively movable to first and second circuit closing positions in which said first contact element respectively engages one or the other of said two second contact elements, a two-winding polar biased re:- peater relay having an armature biased to a first position and operable to a second position when the net resultant flux in said relay is in a given direction and above a given level, contact means operated by said armature and comprising a fixed member and a single movable member operated to an open or closed position with relation to said fixed element according as said armature occupies its said first or second position respectively, a source of current, a pickup circuit including said source and both windings of said repeater relay connected in series to create additive fluxes having a net resultant in said given direction and above said given level to operate said armature to its said second position and completed by the contact elements of saidmaster relay in their said first circuit closing position, whereby the operation of said armature of said repeater relay to its said second position checks the integrity of both windings of said repeater relay and their respective circuit connections, a holding circuit including said source and one of said two windings of said repeater relay and completed by said single movable member of said contact means in its closed position, said holding circuit shunting the other of said two windings of said repeater relay .and the contact elements of said master relay in their said first circuit closing position, and a release circuit including said source and said single movable member of said contact means in its closed position and saidother winding of said repeater 10 relay and completed by the contact elements of said master relay in their said second circuit closing position, said other winding when energized in its release circuit creating a flux opposing that set up by the said one winding energized in its holding circuit.

CLARENCE S. SNAVELY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

